WiMAX (Worldwide interoperability for Microwave Access) is one of wireless broadband communication systems being standardized in the IEEE (Institute of Electrical and Electronic Engineers). For example, installation of a function of a short distance wireless communication system, such as Bluetooth® or WLAN (Wireless Local Aria Network), to a mobile terminal complying with the wireless broadband communication system such as WiMAX makes the mobile terminal to solely perform a variety of functions.
Here, the frequency band of WiMAX and the frequency of Bluetooth or WLAN overlap around 2.4 GHz. In other words, the same frequency is competitively used by a number of communication systems. For this reason, if a mobile terminal which supports both communication of WiMAX and communication of Bluetooth or WLAN carries out the both communication at the same time through the overlapping frequency, one of communications interferes with the other communication, which may be a cause of lowering the throughput.
In order to inhibit interference among a number of communication systems that uses the same wireless resource (e.g., frequency, timing), one of effective solutions is to control timings of data transmission and data reception of respective communication systems so as not to overlap by allocating a wireless resource to respective communication systems through the TDM (Time Division Multiplexing) scheme.
For example, Patent Literature 1 describes a technique of, in a mobile terminal which can transmit and receive signals of a communication system (hereinafter sometimes called WiMAX system) of WiMAX and signals of a communication system (hereinafter sometimes called Bluetooth system) of Bluetooth, transmitting and receiving the signals of the Bluetooth system at a frame timing while the WiMAX system is in a sleep mode. Patent Literature 1: U.S. Patent Application Publication No. US 2007/0232358
In a wireless communication system which carries out data transmission and data reception through the use of wireless frames synchronized with a base station, the base station intensively controls allocation of wireless resource.
In this case, for example, it is inconvenient that a mobile terminal confirming to a number of communication systems independently decides to release a wireless resource allocated to transmission of one of the communication systems and to use the released resource for transmission of another one of communication without negotiation with the base station.
To avoid this inconvenience, the base station controls allocation of the wireless resource to a mobile terminal communicable through a number of communication systems using the same wireless resource (e.g., frequency) through the use of the TDM scheme or the like such that timings of signal transmission and receiving of the respective communication system overlap.
However, increase in the number of mobile terminals connected to a base station complicates management of the wireless resource by the base station. Specifically in this case, the base station negotiates with each individual mobile terminal and controls the above allocation of the wireless resource to the individual mobile terminal.
That increases processing load on the base station, so that the throughput of communication with each mobile terminal may be lowered.